This Demonstration allows you to visualize the distortion of a uniform magnetic field due to the presence of a point magnetic dipole. It is interesting that in this configuration, there exists a sphere through which no magnetic flux passes. This occurs at the characteristic radius where is the magnetic moment of the dipole (in erg/gauss) and is the magnitude of the uniform magnetic field (in gauss). This result can be derived by setting the sum of the radial contributions from the dipole and external field equal to zero, then solving for .
You can change the magnetic field by dragging the locator around the plot area. You can also change the magnitudes of and with the sliders.